More specifically, such a device for forming thin films by means of a plasma-assisted deposit of chemical vapor includes a low-pressure tank enclosing at least one gas reagent, at least two substrata in the form support plates for the thin film, and at least one polarized electrode in the form of a plasma-generating plate, said electrode being placed between the substrate, which are placed essentially parallel and separated from one another by an intermediate space. Various studies have been done on this type of device. The technique proposes in particular a device having a low-pressure tank in which are placed a support plate, called a substratum, onto which will be deposited the thin film after decomposition of the gas reagents, and a full plate, polarized and situated opposite said substratum, connected to a radio-frequency source. The substratum and the tank are generally grounded. However, the effectiveness of this type of device, i.e., the amount of material actually deposited onto the substratum in relation to the amount of material utilized, and its energy yield, are relatively low and dependent on the geometry of the device.
In addition, the device must be designed so as to allow easy maintenance, since the electrodes and other walls of the device are regularly covered over by a growing thickness of deposit that should be regularly removed, either by plasma-cutting (etching) or by the action of an operator. In fact, in most of the known devices, the film formed by decomposition of the gas reagents is deposited not only on the substratum but also throughout the tank.